The purposes of this dissertation were to determine: 1) the relationship betweenmuscle thickness change (MTC) as measured by rehabilitative ultrasound imaging(RUSI) and EMG activity in the lumbar multifidus (LM), 2) if motor control changesproduced by experimentally induced pain are measurable with RUSI, 3) if a differenceexists in MTC between subjects with low back pain (LBP) classified in the treatmentbasedclassification system (TBC) system and controls, 4) if MTC improves followingintervention.Current literature suggests sub-groups of patients with LBP exist and responddifferently to treatment, challenging whether the majority of LBP is "nonspecific". TheTBC system categorizes subjects into one of four categories (stabilization, mobilization,direction specific exercise, or traction). Currently, only stabilization subjects receive anintervention emphasizing stability. Because recent research has demonstrated that motorcontrol impairments of lumbar stabilizing muscles are present in most subjects with LBP,it is hypothesized that impairments may be present across the TBC classifications.Study 1: Established the relationship between MTC as measured by RUSI andEMG in the LM. Study 2: Assessed MTC of the LM during control and painfulconditions to determine if induced pain changes in LM and transverse abdominis (TrA)are measurable with RUSI. Study 3: Measured MTC of the LM and TrA in subjects withLBP classified in the TBC system and 20 controls. Subjects completed a stabilizationprogram and were re-tested.The inter-tester reliability of the RUSI measurements was excellent (ICC3,3 =.91,SEM=3.2%). There was a curvilinear relationship (r = .79) between thickness changeand EMG activity. There was a significant difference (p andlt; .01) between control andpainful conditions on 4 of the 5 LM tasks tested and on the TrA task. There was adifference in MTC between subjects and controls on the loaded LM test which varied bylevel and category. All categories were different from control on the TrA. Followingintervention the TrA MTC improved (p andlt; .01). The LM MTC did not (p values from .13-.86).These findings suggest MTC can be clinically measured and that deficits existwithin TBC system. Significant disability and pain reduction were measured.

No description available.

Hyperlordosis or anterior pelvic tilt is a common non-neutral spinal posture associated with weak core stability, low back pain and altered lumbopelvic muscle activation patterns. Yet the effects of altered lumbopelvic posture and core stability on muscle activation patterns have not been evaluated during a functional movement. The main purpose of this study was to determine the relationship between pelvic tilt, core stability and muscle activation patterns during non-weighted squats in U/19 university-level rugby union players. A total of 49 rugby union players participated in this study. Pelvic tilt (dominant side) was measured from a digital photo with clear reflector markers on the anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS) using the Kinovea video analysis software programme (version 0.8.15). Flexibility of the hamstrings, hip flexors and knee extensors was assessed with goniometry. Core stability was assessed using the pressure biofeedback unit and muscle onset times during the ascent phase of non-weighted squats. The onset times of the transverse abdominis (TrA), erector spinae (ES), gluteus maximus (GM) and biceps femoris (BF) muscles were measured using electromyography (EMG). Players were then grouped according to pelvic tilt (anterior and neutral) and by playing position (forwards and backs). The between group differences were evaluated for the abovementioned variables using p-value (statistical significance) and d-value (practical significance) measures. Muscle activation patterns and firing order were determined using descriptive statistics. The mean pelvic tilt of all participants (N=49) was an anterior tilt of 15.35°. When grouped by pelvic tilt, the anterior tilt group showed a mean pelvic tilt of 17.83° (n=27) and the neutral pelvic tilt group showed a mean pelvic tilt of 11.75° (n=22). Despite the differences in pelvic tilt, there was no significant difference in flexibility between the groups. Another controversial result is that the anterior tilt group showed practical significantly better core stability (d=0.54) than the neutral tilt group (46.93° vs 56.3°). During the double leg squat the muscle activation patterns were consistent between the groups. TrA activated first, followed by ES. Thereafter, the BF muscle activated, followed by the GM. The first place activation of TrA is consistent with the literature stating that the deep abdominal stabilisers of individuals with good core stability activate before the movement is initiated. The early onset of muscle activity of ES points to a focus on back extension during the ascent of the squat. Because the pelvic tilt was measured during static standing only, it is unclear whether the players in the neutral tilt group were able to hold the neutral pelvic tilt posture throughout the movement. Research has shown that there is an increased focus on trunk extension during the ascent phase of the squat which is not present during the descent. Future research should focus on assessing the pelvic tilt at the beginning of the ascent phase of the squat to ensure accurate results. The delay in GM activation during the ascent of the squat is concerning. GM acts as a lumbopelvic stabilizer, and its slow activation points to a decrease in lumbopelvic stability. This is very important in weight training, because weight training increases the strain on the lumbar spinal structures, which decreases performance and increases the risk of injury. / MSc (Biokinetics), North-West University, Potchefstroom Campus, 2014

Hyperlordosis or anterior pelvic tilt is a common non-neutral spinal posture associated with weak core stability, low back pain and altered lumbopelvic muscle activation patterns. Yet the effects of altered lumbopelvic posture and core stability on muscle activation patterns have not been evaluated during a functional movement. The main purpose of this study was to determine the relationship between pelvic tilt, core stability and muscle activation patterns during non-weighted squats in U/19 university-level rugby union players. A total of 49 rugby union players participated in this study. Pelvic tilt (dominant side) was measured from a digital photo with clear reflector markers on the anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS) using the Kinovea video analysis software programme (version 0.8.15). Flexibility of the hamstrings, hip flexors and knee extensors was assessed with goniometry. Core stability was assessed using the pressure biofeedback unit and muscle onset times during the ascent phase of non-weighted squats. The onset times of the transverse abdominis (TrA), erector spinae (ES), gluteus maximus (GM) and biceps femoris (BF) muscles were measured using electromyography (EMG). Players were then grouped according to pelvic tilt (anterior and neutral) and by playing position (forwards and backs). The between group differences were evaluated for the abovementioned variables using p-value (statistical significance) and d-value (practical significance) measures. Muscle activation patterns and firing order were determined using descriptive statistics. The mean pelvic tilt of all participants (N=49) was an anterior tilt of 15.35°. When grouped by pelvic tilt, the anterior tilt group showed a mean pelvic tilt of 17.83° (n=27) and the neutral pelvic tilt group showed a mean pelvic tilt of 11.75° (n=22). Despite the differences in pelvic tilt, there was no significant difference in flexibility between the groups. Another controversial result is that the anterior tilt group showed practical significantly better core stability (d=0.54) than the neutral tilt group (46.93° vs 56.3°). During the double leg squat the muscle activation patterns were consistent between the groups. TrA activated first, followed by ES. Thereafter, the BF muscle activated, followed by the GM. The first place activation of TrA is consistent with the literature stating that the deep abdominal stabilisers of individuals with good core stability activate before the movement is initiated. The early onset of muscle activity of ES points to a focus on back extension during the ascent of the squat. Because the pelvic tilt was measured during static standing only, it is unclear whether the players in the neutral tilt group were able to hold the neutral pelvic tilt posture throughout the movement. Research has shown that there is an increased focus on trunk extension during the ascent phase of the squat which is not present during the descent. Future research should focus on assessing the pelvic tilt at the beginning of the ascent phase of the squat to ensure accurate results. The delay in GM activation during the ascent of the squat is concerning. GM acts as a lumbopelvic stabilizer, and its slow activation points to a decrease in lumbopelvic stability. This is very important in weight training, because weight training increases the strain on the lumbar spinal structures, which decreases performance and increases the risk of injury. / MSc (Biokinetics), North-West University, Potchefstroom Campus, 2014

Activating the core muscles through exercise training programs is believed to be important for athletic performance. Considerable attention has been credited to the lumbar multifidus, transverse abdominis, and quadratus lumborum in designing exercise training programs. Numerous core exercise claims and recommendations abound in the fitness and physical therapy communities touting a superior core challenge for these muscles. The plethora of core activation literature with conflicting outcomes has convoluted the process of choosing exercises for an optimal core training approach. Although an abundance of research studies have quantified the muscle activity, collectively, a consensus on the type of exercise that elicits the largest muscle activity does not exist. Therefore, the objective of this investigation was to critically examine the literature and synthesize the muscle activity produced across various physical fitness exercises to determine which type of exercise elicits the largest amplitude for the core muscles in healthy individuals. PubMed, EMBASE, SPORTdiscus, CINAHL, (CCRT) and Web of Science databases were searched revealing 27 studies meeting the inclusion criteria measuring EMG activity during 202 exercises. In absence of research for the quadratus lumborum, no conclusions could be made and bring about concern for current recommendations. Furthermore, the methodological diversity significantly limited the quality of studies meriting standardization for future EMG research. Nonetheless, the current evidence suggests free weight exercises and non-core exercises using external resistances produce the largest EMG activity for the lumbar multifidus and transverse abdominis, respectively.